A recent series of experiments have demonstrated the feasibility of producing increases of recall over time--hypermnesia--in a controlled laboratory setting. Multiple forced-recall trails following stimulus input yield progressive net increases in recell. The effect is readily obtained with pictures as stimulu but not, suprisingly, with words. The proposed research seeks to elucidate the nature of this phenomenon. Of special interest is the extent to which the processor can exercise selective control over hypermnesia, an issue potentially basic to the cognitive analysis of repression, memory dumping, and other forms of biased information handling in memory. Thus: Can subjects increment selected memories (selective hypermnesia)? If so, would such amplification of selected memory traces occur at the expense of other memories (selective amnesia)? Can suubjects self-induce hypermnesia for words by activity recoding verbal input into imaginal codes? The proposed research addresses itself to the following additional questions: Are there developmental trends in the spontaneous recoding of verbal inputs into images? Specifically, do children, more than adults, tend spontaneously to recode verbal inputs into imaginal codes and consequently produce spontaneous hypermnesia for verbal inputs? What interpolated covert activity between recall attemps (fantasy, directed thinking, image generation, rest, etc.) maximizes hypermnesia? Can the well established difference between picture and word recognition furnish an explanation for the picture-word difference in multi-trail recall (i.e., hypermnesia for pictures but not words)? Finally, is imagery (imaginal coding) the common denominator underlying a variety of controversial hypermnesic phenomena such as reminiscence, recoveries of lost memories in therapy, aDd hypnotic hypermnesia?